Continuous phase modulation

About: Continuous phase modulation is a research topic. Over the lifetime, 3199 publications have been published within this topic receiving 37245 citations. The topic is also known as: CPM.

System and apparatus for designing and producing signalling waveforms for direct-sequence code division multiple access communications

Abstract: A method of identifying direct sequence CDMA pulse shapes which optimize a cost function subject to various constraints. The cost function may either be an acquisition SNR or an interference power. The method may be applied to both full-response pulse shapes and partial-response pulse shapes. The constraints include a quasi-constant envelope constraint, a continuous phase constraint, a spectral nulls constraint, and an ISI-free constraint. The Fourier transform of a desired pulse shape is expressed in terms of a finite sum of prolate spheroidal wave functions. The cost function and the constraints are also expressed in terms of this finite sum. Numerical methods software determines the optimal solution. This may be used to produce finite impulse response filters which generate the desired pulse shape.

Doubly Iterative Equalization of Continuous-Phase Modulation

Abstract: In this paper, a doubly iterative receiver is proposed for joint turbo equalization, demodulation, and decoding of coded binary continuous-phase modulation (CPM) in multipath fading channels. The proposed receiver consists of three soft-input soft-output (SISO) blocks: a front-end soft-information-aided minimum mean square error (MMSE) equalizer followed by a CPM demodulator and a back-end channel decoder. The MMSE equalizer, combined with an a priori soft-interference canceler (SIC) and an a posteriori probability mapper, forms a SISO processor suitable for iterative processing that considers discrete-time CPM symbols which belong to a finite alphabet. The SISO CPM demodulator and the SISO channel decoder are both implemented by the a posteriori probability algorithm. The proposed doubly iterative receiver has a central demodulator coupled with both the front-end equalizer and the back-end channel decoder. A few back-end demodulation/decoding iterations are performed for each equalization iteration so as to improve the a priori information for the equalizer. As presented in the extrinsic information transfer (EXIT) chart analysis and simulation results for different multipath fading channels, this provides not only faster convergence to low bit error rates, but also lower computational complexity.

Polar transmitter for increasing modulation rate using multi-phase generator

Abstract: Provided is a polar transmitter which increases a modulation rate using a multi-phase generator and includes: a data processor which processes and separates incoming data to an amplitude component and a phase component; a multi-phase generator which generates a plurality of carriers having a plurality of phase components by processing a carrier having a certain frequency; a selection output part which selects and outputs a carrier having a phase substantially equal to the phase component; and a carrier output part which synthesizes the output carrier with the amplitude component and outputs a carrier. Accordingly, the modulation rate of the carrier can be increased and the bandwidth can be extended with the related art polar transmitter. Therefore, the polar transmitter is applicable to the wideband communications, the multi-mode, and the multi-band.

Analysis of power spectrum of continuous phase waveforms for binary modulation communications

Abstract: In this paper a throughput efficient modulation method based on the idea of continuous phase is devised, namely the continuous phase extended binary phase shift keying (CPEBPSK), which satisfies increasingly greater demand for the performance of communication systems. The detailed analysis of the corresponding power spectrum is derived by a universal way that is suitable for the binary modulation of ultra narrow band (UNB) communications. Simulation results illustrate the validity of theoretical spectrum analysis, which prove that this UNB system having high spectral efficiency. On this basis, the bandwidth is studied that indicates the CP-EBPSK technology belongs to the category of the UNB throughput-efficient communications.

Sparse graph-based coding schemes for continuous phase modulations

Abstract: The use of the continuous phase modulation (CPM) is interesting when the channel represents a strong non-linearity and in the case of limited spectral support; particularly for the uplink, where the satellite holds an amplifier per carrier, and for downlinks where the terminal equipment works very close to the saturation region. Numerous studies have been conducted on this issue but the proposed solutions use iterative CPM demodulation/decoding concatenated with convolutional or block error correcting codes. The use of LDPC codes has not yet been introduced. Particularly, no works, to our knowledge, have been done on the optimization of sparse graph-based codes adapted for the context described here. In this study, we propose to perform the asymptotic analysis and the design of turbo-CPM systems based on the optimization of sparse graph-based codes. Moreover, an analysis on the corresponding receiver will be done.